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Re: [TCML] Stuck at 36"



Hi Bill,

If I calculated it properly, your overall tank capacitance is somewhere around 0.038 uF, and your NST bank is faceplate rated at 7.5 kV at 180 mA. The optimal tank capacitor for this configuration (when using a static gap) would be about 1.6 times the "mains resonant" capacitance (0.064 uF) or about 0.1 uF.

The reason you're hitting a wall is that you're being "power limited" by the relatively small size of your tank capacitor. Your "bang size" is presently only about 1/3 of the optimal size. Thus, at a given break rate, the amount of power that can be delivered by your coil's primary circuit (i.e., bang size x break rate) is also only about 1/3 of what it could be with the proper size tank cap. So even though your NST bank has the capability to deliver longer sparks, your tank cap does not.

I'd recommend adding about 0.07 uF MMC to supplement your existing capacitor bank, or replace the homemade caps entirely with a 0.1 uF MMC bank to save space.

Bert
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b.jbohn@xxxxxxxxxxx wrote:
Hello everyone, first time here (great site!).  I've built a coil
that refuses to put a streamer past 36" to a grounded plate suspended
vertically at the top of the secondary.  Occassionally I'll get one
41-42".

I'm using NST's 1@60Ma 7.5kv 4@30Ma 7.5kv all hooked together.  I
think they're all okay because if I remove any one of them from the
system performance diminishes.

The secondary coil that I've had the best luck with is wound on a
5-1/4" varnished paper tube winding length 22-1/2" the wire is .014
or #27 magnet it's 1,607 turns 2,208 feet.

My capacitors are a mixed batch of homemade HDPE plate type.

Caps #1 & 2 each contain aluminum plates 10 x 12" 16 plates each .090
HDPE between each plate

Caps #3 & 4 each contain aluminum plates 4-1/2 x 9" 40 plates each
.060 HDPE between each plate

Cap #5 rolled type in oil .01583 MFD

All capacitors are in oil.

My spark gap is a segmented type with 10 copper tubes 7/8 OD 5" long
total space between gaps is .150" just enough so the transformers can
break. The gap is also blown with a fan.

My primary is a 1/4" copper tube conical 15 degree 14 turns 23" OD
7-1/2" ID seems best tapped at 12 to 13 turns.  I'm using a spun
toroid it is 4-1/2 x 18" that size seems to work the best although if
I put a 6" sphere on top pretty cool stuff happens (the streamers
jump around the toroid and ball).  I have other secondaries that I've
tried but this one is the best.  I have looked at other coils on this
listing and other websites and I think mine should be doing better
than 36".  Any input appreciated!

Bill _______________________________________________ Tesla mailing
list Tesla@xxxxxxxxxxxxxx http://www.pupman.com/mailman/listinfo/tesla



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